The measurement of time is a concept which, while perhaps grasped in the abstract, may be difficult to understand in a more rigorous manner. It is sometimes difficult, for example, for a child to recognize and appreciate that, when it is the middle of the day in New York, it is the middle of the night in China. Further, when a clock indicates 12 noon in New York, why do clocks in Los Angeles say it is 9:00 in the morning? The teaching of the foregoing and related concepts can be facilitated by a model of the earth in which the relationship between the rotation of the earth about its axis and the passage of time and the relationship of the various points on the earth with respect to both local time and to the solar day at a particular time can be depicted.
Model globes have been developed to illustrate and present the illumination of the earth by the sun. Such globes can inferentially display the relationship of clock time to rotation of the earth. Yet such globes do not sufficiently depict the relationship of local time to the earth's rotation, or illustrate how local time varies across the world.
It is accordingly a purpose of the present invention to provide a model globe in which a representation of the illumination of the earth by the sun can be presented.
A further purpose of the present invention is to provide a model globe of the earth in which the rotation of the earth about its axis, and the effect of such rotation upon the illumination of the earth's surface by the sun can be illustrated.
Still a further purpose of the present invention is to provide a model globe in which relative clock time for different locations on the globe can be compared and presented.
Another purpose of the present invention is to provide a model globe in which local clock time for a chosen location can be displayed and varied in conjunction with the rotation of the globe about its axis.
Yet another purpose of the present invention is to provide a model globe in conjunction with a clock face which has a hand which rotates about the clock face to depict the passage of time in association with globe rotation.